An improved copper converting process of top blowing with gas containing oxygen in combination with bottom sparging was disclosed by Marcuson et al. in U.S. Pat. No. 4,830,667. In Marcuson et al., a molten copper sulfide bath was top blown with oxygen to form free Cu and SO.sub.2 gas. The molten bath was simultaneously sparged to improve oxygen efficiency and decrease amount of copper oxide formed in relation to amount of nickel oxide formed. The process of one '667 patent has achieved levels of high oxygen efficiency with relatively short cycle times causing a tendency to overheat nonferrous metal. Overheating of nonferrous metal is undesirable because it tends to substantially reduce refractory life and product quality.
Conventionally, lance designs have been both relatively complex and relatively expensive to maintain. Lances have penetrated the hot zone of a furnace to a position above or submerged in molten copper. Several lance designs require extensive cooling to limit oxidation or melting of the lance. Cooling has generally been accomplished by water cooling or gas shrouding. An example of a water cooled lance was provided by H. Smeikal in Canadian Patent No. 1,008,661. Smeikal disclosed a lance having increased cooling passage cross-section in regions exposed to the greatest amount of heat. Kimura et al. in Sumitomo's Canadian Patent No. 1,234,292, illustrated a conventional converter lance arrangement in which high pressure (1 to 3 kg/cm.sup.2) oxygen was blown vertically at a molten bath in combination with forcing air through tuyeres. In Sumitomo's patent the height of the lance was maintained within 0.4 m of the molten bath to ensure a high oxygen velocity at impact.
A water cooled lance having a design feature to prevent clogging from splashing of molten metal, matte or slag was disclosed by L. Jaquay in Canadian Patent No. 1,042,207. Another lance system for "simplified" maintenance was disclosed by Suglura et al. of Mitsubishi in Canadian Patent No. 1,035,575. Suglura et al. disclosed a lance vertically adjusted for simplified lance replacement and height adjustment. Mitsubishi lances are disposable pipes which are non-water cooled; and they have to be replaced at a relatively rapid rate. Additionally, Mitsubishi lances are continually rotated to promote even wear. Several relatively complicated lance designs, ideas, systems and procedures have been suggested for providing a lance having improved reliability, operability and efficiency.
It is an object of this invention to provide a quick, efficient method of purifying nonferrous materials by reaction with oxygen.
It is a further object of this invention to provide a converter means including a lance which limits splashing of molten materials which can clog lances and accelerate refractory erosion.